AS/Sea Trout vs. SB?

[Kype]

Is the S bass recovery a detriment to sea trout populations and Atlantic salmon Restoration?

[The Fisherman]

I have no emprirical data to work with, but my guess would be yes.

OTOH, even when striped bass stocks were collapsing in the 80's, I still never saw anyone catch a sea run brown. (Still haven't ever seen/caught one).

[Jon]

My guess would be that healthy, viable populations of each species would co-exist, as they do in other parts of the world. Unfortunately, pollution and other human interventions have seen to it that we're not likely to find out anytime soon...

[Andrew]

I certainly don't know, but might be able to dredge up some research papers on the subject.

But, it's worth keeping in mind that historically (as in very long term, i.e. ecological and evolutionary time scales) striper populations were much higher than they are now (or at least this is my understanding). So even if current striper populations are a problem for salmonid restoration, it can only be "their fault" in the context of other modern problems facing the salmonids.


I'll see if I can find any papers on the subject.


(By the way, this is a really hot topic right now in California, where it's about - or at least perceived to be about - stripers vs. Pacific salmon)

[Andrew]

Did some digging through some online scientific publication search engines, and came up with a few papers that look like good starting points. When I get time, I'll see if I can download them or find them here at my library.

(At least one of them reported that salmon smolts made up something like 60% of the biomass consumed by stripers in one particular river!!)

[Andrew]

I dug up a few papers that have tried to address this issue. None that I could find could be considered "proof" of much, but I think the general interpretation could be safely said to be "Certainly, it is possible, and more likely probable, that increased striped bass populations aren't helping the salmon."

First, there are studies supporting the idea that increasing striper populations are responsible for declines in other fish, such as American shad and blueback herring.

Second, striper predation on salmon smolts has been documented, and in at least one study, smolts constituted over 80% of the total mass of food remains found in stripers (this was below a dam, which probably concentrated both species).

Third, in some areas there are negative correlations between documented striper and salmon returns (e.g. Penobscot and St. Croix rivers). (However, others, like the Connecticut and Merrimack rivers, did not show this pattern)

Anyway, that's what I gleaned from a cursory examination of a few papers. It's also important to keep in mind that other fish eat smolts. Apparently, the slimy sculpin is a major smolt eater.


Andrew

[SloNDeep]

Bellies full o' smolts is proof enough for me

Timing coincident with Herring runs?

Lots of Stripers in the rivers when smolts are heading out?

If anecdotal evidence is good enough to believe AS ran the CT river in good numbers historically, it's good enough to believe the Stripers are wipin them out now.

[paul young]

the striper population crashed in the late 70's- early 80's because of poor or non-existent regulations on both commercial and sport fishing harvest levels.

so we had a MORATORIUM.....

10 years later.....striped bass in huge numbers. BUT....we have kept the same restrictive regs even though the population was at historically very high numbers. this was good news to the sportfishing community. it made even entry-level bass anglers look good.

i think it is detrimental to a many different fish populations, among them atlantic salmon and sea-run trout.

i owned/operated a charter boat in eastern li sound for 8 years and hook/line commercial fished for bass another 10, and i can tell you i have seen them regurgitate everything that swims out there. all it needs to do to become a meal is to fit in their mouths.

the attitude of "kill at will" is what depressed the population. unfortunately the pendulum has now swung to the other end of the arc, and that is equally poor stewardship of the resource. IMHDAO...-paul

[Andrew]

It's certainly true that stripers will eat anything. I saw one study that found a garter snake inside one (my next fly tying project!).

But, I think the study that found that 80% of the biomass inside these stripers was AS smolts was unusual in that both fish were backed up against a hydroelectric dam. Still bad news for the salmon, but not necessarily an indication that there are "too many" stripers.

What most of the papers I read seemed to agree upon was that salmon are having trouble because they are at such low numbers, they can't get a foot hold. They could compensate for predation by stripers, brook trout, sculpin, etc if they could get above some critical threshold.

Apparently, some of the streams that the salmon returned to had slimy sculpin and some did not, and the authors of this paper suggested that if streams without significant predators could be the main focus of current reintroduction efforts, perhaps the salmon would have a better chance of reaching those numbers where they could then survive in the other streams and rivers as well.


Personally, I'm not crazy about the idea of increasing striper harvesting because I think there are still some scientists who worry about the quality of some of the major striper breeding grounds, and whether certain year classes are simply just missing. But I also admit that I like stripers, and I have no history with salmon, having not grown up on the east coast at all. The fisherman in me likes stripers; the biologist in me appreciates biodiversity for its own sake...that part of me might be willing to harvest a few bass if it would help the salmon.

Andrew

[flyrodder]

I find it hard to believe that striper populations would be detrimental to other fish populations. These fish co-existed for thousands of years before the intervention of man.

[The Patriot]

What flyrodder said..... I was just thinking that before he posted it...

Atlantic Salmon (I hate when people call them AS.... you know, like calling Rainbows "Bows", or cigars "Gars", or calling Bamboo "BOO"... ;) :D)

Atlantic Salmon and Striped Bass presumably coexisted in our seas and rivers in great numbers in the 17th, 18th, and perhaps the 19th centuries, if we are to believe our various history sources. The Native Americans and early colonists are said to have harvested both Stripers and Salmon within their respective ranges, according to historical accounts from Cape Cod, Colonial Williamsburg and Jamestown VA., etc. I recall reading one historical account wherein the author proclaimed that stripers were so thick, one could practically walk across the water on their backs..... so why should this be a problem now?

Could it be that the Salmon were missing for so long, that the Stripers filled in their biological niche? And then the Stripers too were decimated, but having recovered are still preventing the Salmon from gaining a foothold?

Interesting......

[Eric L]

Do Striped bass eat Atlantic salmon smolts?

Of course!

They also eat stocked trout in CT where they have access to them ;-)

Is striped bass predation responsible for the failure of Atlantic Salmon restoration efforts south of Maine?

No!

Return rates were as dismal in the 70's and 80's (when striped bass were scarce) as they are today. The primary problems with restoration efforts are most likely some combination of: dams (no/poor upstream passage, terrible downstream passage); competiton and predation from non-native fish such as brown trout and smallmouth bass; habitat degredation (both in spawning areas and in Long Island Sound). Also, at sea survivorship and return rates for even relatively healthy Atlantic salmon populations in Canada are very low relative to historic averages.

As a side note, down here in Chesapeake Bay the blue crab population is way down (or crashing depending on your point of view) and tighter fishing reguations have been imposed. The local watermen blame much of the blue crab problems on there being too many striped bass in Chesapeake Bay that are eating all of the juvenile crabs. Some of them argue that if we could only increase the harvest of striped bass in the Bay that this will reduce predation pressure on the crabs and allow them to bounce back. Not that they are not correct about the bass eating alot of crabs (it is true), but harvesting down one species to improve the recruitment of another has few examples of success and may result in a situation where both species are overharvested.

Regards,

Eric

[The Fisherman]

I love the use of the word "watermen." James Michener would be proud.

[paul young]

fisherman,

the 2nd sentence of your above post says it all......

we have put the sea runs and salmon on the ropes due to our meddling. now there aren't enough of them left to compete succesfully and maintain their niche in the ecosystem we have as it exists today.

we can help them recover......or kiss them goodbye. we may well have to anyway, but i hate to give up.

please join ASF today.-paul

[flyrodder]

Don't forget that the salmon smolts make great snacks for the trout we love to catch. Back when there was a salmon run here the spawning grounds of the salmon were not overrun by brown and rainbow trout.

I should revise my original post to say that in a completely natural environment it is very unlikely that one species will wipe out another. There are predator-prey cycles that have existed in nature for millions of years. When we harvest species to the brink of extinction and introduce non-native invasive species, we screw with the natural order of things.

[flyrodder]

For more information on predator-prey cycles, see:

http://en.wikipedia.org/wiki/Lotka-Volterra_equation

http://www.tiem.utk.edu/bioed/bealsmodules/predator-prey.html

[Andrew]

I think I said in the original post about those papers that the authors of these studies stated that the problems between stripers and salmon was due to the fact that salmon populations were already low when the striper resurgence started. I don't think any of these authors would argue that stripers simply drove Atlantic salmon extinct. It's one thing to weather a storm in a big boat, another all together if you're already in a sinking dingy.


And, as I also said, all of these studies are based on examining correlations and trying to control for confounding variables, but you can never establish cause and effect definitely this way. FOr that you need experiments, but of course that's hard to do when you're dealing with rare animals.

[Kype]

I don't think there is anything simple about AS restoration but I think there needed to be some co-ordination of strip stock recovery with Atlantic salmon restoration. People just don't work together. In order for AS smolt to have a chance there needs to be massive numbers of out migrating smolt. At present the Fed has stifled the one source of massive numbers of juvenile salmon. Massive numbers of salmon can only come from outsourcing to the Aqua Culture industry. I know all the problems of the Aqua Culture industry blab bla bla etc etc. We have invested in a breeding program destined to produce idiot fish. There simply isn't enough diversity within the gene pool. Returning fish are too few and we continue to in breed. It is time for a change.

The Aqua Culture industry was willing to work with the restoration effort in Maine. They agreed to provide 20,000 adult pre-spawning adult fish to be stocked out with the return fish to bolster natural reproduction potential. Nothing like natural selection! They also agreed to provide multi millions of feeding fry. The numbers of which the Maine Sea Run Salmon Commission was unable raise. They agreed to do this keeping the stock no more than 2 generations from returning adult salmon. In stead of trying this the Aqua Culture Industry was given the boot from Maine. Now look at what we have.

I seem to recall far better returns in the late 1970's and early 1980's than we have now. Things were looking up for AS back then. Just look at the historic returns.

We have to let go the BS about how things use to be before the settiling of this region. It isn't ever going to back to those times but the situation can be improved if people keep an open mind and try different things. At this point we are doing what has failed for quite some time now.

Bobby